Filter device and filter element for use with such a filter device

ABSTRACT

A filter device having at least one filter housing ( 1 ), in which at least one filter element ( 11 ) that defines a longitudinal axis can be received in the form of a filter cartridge which has on at least one end an end cap ( 19 ) forming an enclosure for the relevant end rim of the filter material ( 23, 25 ), which end cap, for fixing the position of the filter element ( 11 ) in its functional position, can be fixed on an element receiver ( 13 ) that interacts with the bottom part ( 7 ) of the filter housing ( 1 ), is characterized in that the element receiver ( 13 ) and the assigned end cap ( 19 ) of the filter element ( 11 ), on the parts thereof ( 17  and  15 ) coming into engagement with one another in the functional position of the filter element are provided with shape irregularities which are matched to one another which enable the engagement in a positional relationship directed towards one another.

The invention relates to a filter device having at least one filter housing in which at least one filter element which defines a longitudinal axis can be accommodated in the form of a filter cartridge which on at least one end has an end cap that forms an enclosure for the pertinent end edge of the filter material and which can be fixed on an element receiver which interacts with the bottom part of the filter housing for fixing the position of the filter element in its functional position. The invention also relates to a filter element for this filter device.

Filter devices of this type are readily available commercially in different versions. To a large extent, these filter devices are used for filtering working fluids, such as hydraulic fluids, fuels, lubricants, and the like. In fluid systems, specifically hydraulic systems in which filter devices are used, the operational reliability of the system depends largely on the reliable operation of the filter devices that are located in the system. In other words, in addition to the failure of the pertinent system, a failure of the filter device can lead to serious damage to the system and thus can cause significant economic loss.

DE 10 2005 045 012 A1 relates to a generic filter device with a housing for holding a filter element consisting of at least two housing parts which can be detachably connected to one another, a support tube, and a filter material which surrounds the support tube, with the ends of the support tube and filter material discharging into at least one receiving part. The filter material can be withdrawn in one direction to separate it from the support tube, and in this withdrawal direction both the support tube and also equally the filter material are provided with a definable conicity, as a result of which the fouled filter material can be easily withdrawn from the support tube. The support tube can be re-used in conjunction with a newly inserted filter material together with its receiver parts. The receiver parts for the filter material form end caps, and the transition between the filter material and the support which has been formed in this way is seamless due to the end caps, which can be molded on in the form of an upper receiver part and a lower receiver part. The ends of the support tube are held in independent receiver parts. Viewed in the longitudinal direction of the housing, the filter material with its receiver parts is made axially longer than the inner support tube.

With respect to this problem, the object of the invention is to make available a filter device which is characterized by special operational reliability.

According to the invention, this object is characterized by a filter device having the features specified in claim 1 in its entirety.

According to the characterizing part of claim 1, an important particularity of the filter device resides in the fact that both on the element receiver on the bottom part of the filter housing and also on parts of the end cap of the filter element, which cap is assigned to the element receiver, there are irregularities of shape, with the irregularities of shape on the element receiver and on the end cap being matched to one another such that when they are aligned to one another they enable mutual engagement. In this way, a pertinent filter element can be moved into the functional position only provided that complementary features of shape on the element receiver and end cap are matched to one another such that they allow the engagement with a corresponding mutual alignment. This ensures that the filter device can be operated solely with a filter element that is intended for a respective special use and that meets the specifications which ensure operational reliability for this purpose and that apply to it.

Thus, it is not only precluded that a filter element will be used that has an unsuitable filter fineness or that is unsuitable for the respective application, i.e., is not assigned to a corresponding pressure stage, but the risk is also avoided that possibly a so-called “discount element” available on the market will be used which does not meet the applicable safety standards.

In advantageous exemplary embodiments, the element receiver has a tube socket which projects from its top and which extends into an inner filter cavity of the filter element in the functional position to form a fluid connection, where the tube socket has, as the irregularity of shape pertinent to the element receiver, an outside contour which diverges from the circular, and it can be an asymmetrical shape.

Especially advantageously, the arrangement can be made such that the end cap of the filter element has a connector which extends into an inner filter cavity of the filter element, which cavity is surrounded by a fluid-permeable support tube, and which is engaged by the tube socket of the element receiver in the functional position of the filter element, where, as the irregularity of shape which is pertinent on the end cap, the opening cross section of the connector is matched to the non-circular outside contour of the tube socket of the element receiver.

In especially advantageous exemplary embodiments in which the tube socket on its outside contour has a side surface which tapers it toward its free end in the manner of a conical surface, processes of changing the filter elements become especially simple and convenient because the conical shape of the tube socket on the element receiver facilitates engagement with the connector of the filter element which is to be inserted.

With respect to the shapes of the contours which are matched to one another, it is possible to proceed such that the outside contour of the tube socket and the opening cross section of the connector each have one segment in the form of a graduated circle which is concentric to the longitudinal axis and a corrugated segment which is nearer relative to the longitudinal axis.

Since to enable the mutual engagement between the end cap and element receiver a given positional relationship is necessary in which the irregularities of shape assume positions that are aligned to one another, the additional advantage arises that the engagement forms a locking element so that, even in the case of a tangential flow that may occur in the filter housing, the filter element is secured against a possible torque around the longitudinal axis.

The defined rotary position of the filter element in the filter housing moreover allows the further advantageous possibility of providing a shielding part on the end cap in a filter housing which has a lateral fluid inlet which is adjacent to the end cap of the filter element which is in the functional position, which shielding part extends along the outside of the filter material of the filter element and, in the functional position of the filter element, overlaps the region of the fluid inlet as impact protection. The fixed rotary position ensures that the impact protection is located in the incident flow region of the filter element. Advantageously, on the side of the end cap opposite the shielding part, there can be a capture magnet which is protected against direct incident flow since it is located in the lee region.

The subject matter of the invention is also a filter element for use with a filter device according to one of claims 1 to 8 which has the features of claim 9 in its entirety.

More detailed features of the shape of the filter element are specified in claim 10.

The invention is explained below using an exemplary embodiment shown in the drawings.

FIG. 1 shows a longitudinal section of one exemplary embodiment of the filter device according to the invention, where the state is shown in which there is a filter element suitable for use in the filter housing in the functional position;

FIG. 2 shows a perspective oblique view of the separately shown element receiver of the exemplary embodiment, drawn on a larger scale than in FIG. 1, and

FIG. 3 shows a perspective oblique view of a filter element, shown reduced in size compared to FIG. 2 and compared to a practical embodiment, looking at the end cap, for the exemplary embodiment of the filter device.

A hollow cylindrical filter housing, which is designated as a whole as 1, has a top part 3, a middle part 5, and a bottom part 7 which are screwed to one another. In particular, the middle part 5 and the bottom part 7 can, however, also be made in one piece. The upper end of the top part 3 opposite the bottom part 7 can be sealed by a screw-on housing cover 9. The housing 1 can accommodate a filter element designated as a whole as 11, coaxially to the longitudinal axis of the housing 1. For positioning and fixing in position, on the bottom part 7 there is an element receiver 13 in the form of a hollow body which is shown separately in FIG. 2 and on whose top facing the filter element 11, there is a specially shaped tube socket 15. For the actual positioning of the filter element 11, this tube socket 15 interacts with a connector 17, which is located on the end cap 19 of the filter element 11 facing the bottom part 7. The connector 17 forms a fluid connection to an inner filter cavity 21 within the filter element 11, which forms the output side in the filtration process.

In FIG. 1, the filter element 11 is made as a two-stage element, where a filter material 23 of coarser filter fineness, which extends on the outside of the filter element 11 on the outside, borders the outer housing space 25 which forms the inlet side in the filtration process and forms a prefilter. The lower edge of the filter material 23 is enclosed on the bottom side by the end cap 19. The top end of the filter material 23 is enclosed by an upper cover cap 27 on which there is a bypass valve arrangement 29 which enables throughflow from the space 25 to the prefiltration space 31 on the inside of the filter material 23 at a given, inlet-side pressure level. When the filter element 11 is made in two stages, the prefiltration space 31 is not directly connected to the connector 17 of the end cap 19, but connected upstream of the connector 17 there is a fine filter unit 33 with a filter material 35 of greater filter fineness which surrounds a fluid-permeable support tube 37, which is open to the connector 17 of the end cap 19 and which, together with the lower edge of the filter material 35, is enclosed on the outside of the connector 17 by the end cap 19. Thus the space 21 which forms the outlet side in the filtration process is connected via the connector 17 to the tube socket 15 of the element receiver 13, from whose bottom the cleaned fluid can emerge via a spring-loaded bottom valve 39. On the inside of the connector 17 provided for engagement of the tube socket 15, there is a seal arrangement with an O-ring 41 in order to create the seal between the connector 17 and the outside of the tube socket 15 in the functional position.

In the exemplary embodiment shown in FIG. 1, the fluid inlet 43 to the inlet-side space 25 on the middle part 5 of the housing is located in the vicinity of the end cap 19 of the filter element 11 which is located in the functional position. As impact protection, on the outside of the end cap 19 in the peripheral region of the filter element 11 facing the inlet 43, a shield plate 45 is mounted which extends arched along the outside of the outer filter material 23 in the pertinent peripheral area. In the lee region which is opposite the fluid inlet 43, which faces away from the incident flow region and in which a flow-damped dirt capture basket is formed, there is a capture magnet 47.

As already stated, the irregularities of shape on the parts of the element receiver 13 and the bottom side end cap 19 of the filter element 11, which parts interact in the functional position, ensure that only a proper filter element 11 can be moved into the functional position and that in the functional position a rotary position of the filter element 11 is dictated in which, on the one hand, the filter element 11 is held locked and, on the other hand, it is ensured that the shielding plate 45 is located as impact protection in the incident flow region and the capture magnet 47 is located in the lee region.

FIGS. 2 and 3 show that for this purpose the tube socket 15 of the element receiver 13 which surrounds the inner passage 49 of the element receiver 13, which passage leads to the bottom valve 39, has a shape which diverges from the circular, specifically such that the outside contour 51 is made asymmetrical. As FIG. 2 shows best, this contour has a segment 53 in the form of the arc of a graduated circle which is concentric to the longitudinal axis and a segment 55 which on the element receiver 13 is placed radially further inward and has a corrugated shape. Complementary thereto, as FIG. 3 shows, the opening cross section of the connector 17 has the shape which fits the latter with the arc-shaped segment 53 and the corrugated segment 55, i.e., an appropriate shape for which the O-ring 41 or another formed seal on the connector 17 provides a seal around the entire periphery on the outside contour of the tube socket 15 in the functional position. As FIG. 3 shows, the shielding plate 45 which forms the impact protection on the end cap 19 is mounted in a peripheral edge depression 57, for example, by cementing the plate 45, optionally made of a plastic material, into the depression 57 of the end cap 19, which is likewise made of plastic.

As FIGS. 1 and 2 show, the tube socket 15 is slightly conically tapered toward its free end because the side surface 59 is slightly tilted to the longitudinal axis. When the filter element is changed, moving connector 17 and tube socket 15 together is made easy and convenient without the risk of damaging the O-ring 41. 

1. A filter device having at least one filter housing (1) in which at least one filter element (11) which defines a longitudinal axis can be accommodated in the form of a filter cartridge which on at least one end has an end cap (19) that forms an enclosure for the pertinent end edge of the filter material (23, 25) and which can be fixed on an element receiver (13) which interacts with the bottom part (7) of the filter housing (1) for fixing the position of the filter element (11) in its functional position, characterized in that the element receiver (13) and the assigned end cap (19) of the filter element (11) in its parts (17 and 15) which engage one another in the functional position of the filter element are provided with irregularities of shape (51) which are matched to one another and which make engagement in the positional relationship aligned to one another possible.
 2. The filter device according to claim 1, characterized in that the element receiver (13) has a tube socket (15) which projects from its top and which extends into an inner filter cavity (21) of the filter element (11) which is in the functional position to form a fluid connection, and that the tube socket (15) has, as the irregularity of shape pertinent to the element receiver (13), an outside contour (51) which diverges from the circular.
 3. The filter device according to claim 2, characterized in that the outside contour (51) of the tube socket (15) is shaped to be asymmetrical.
 4. The filter device according to claim 2, characterized in that the end cap (19) of the filter element (11) has a connector (17) which extends into an inner filter cavity (21) of the filter element (11), which cavity is surrounded by a fluid-permeable support tube (37), and which connector is engaged by the tube socket (15) of the element receiver (13) in the functional position of the filter element (11) and that, as the irregularity of shape which is pertinent to the end cap (19), the opening cross section of the connector (17) is matched to the non-circular outside contour (51) of the tube socket (15) of the element receiver (13).
 5. The filter device according to claim 2, characterized in that the tube socket (15) on its outside contour (51) has a side surface (59) which tapers it toward its free end in the manner of a conical surface.
 6. The filter device according to claim 4, characterized in that the outside contour (51) of the tube socket (15) and the opening cross section of the connector (17) each have one segment (53) in the form of a graduated circle which is concentric to the longitudinal axis and a corrugated segment (55) which is nearer relative to the longitudinal axis.
 7. The filter device according to claim 1, characterized in that the filter housing (1) has a lateral fluid inlet (43) which is adjacent to the end cap (19) of the filter element (11) which is located in the functional position and that on the end cap (19) there is a shielding part (45) which extends along the outside of the filter material (23) of the filter element (11) and in the functional position of the filter element (11) overlaps the region of the fluid inlet (43) as impact protection.
 8. The filter device according to claim 7, characterized in that on the side of the end cap (19) opposite the shielding part (45) there is a capture magnet (47).
 9. A filter element for use with a filter device according to claim 1, which on at least one end has an end cap (19) that forms an enclosure for the pertinent end edge of the filter material (23, 25), which end cap can be fixed on an element receiver (13) which is located on the bottom part (7) of the filter housing (1) for fixing the position of the filter element (11) in its functional position, characterized in that, on parts (17) which in the functional position engage parts (15) of the element receiver (19) in the pertinent filter housing (1), the end cap (19) is provided with an irregularity of shape (51) which is matched to an irregularity of shape, which is located on parts (15) of the element receiver (13) such that, for a positional relationship of the irregularities of shape (51), which relationship is aligned to one another, the engagement between end cap (19) and element receiver (13) is enabled and thus the filter element (11) can be moved into the functional position.
 10. The filter element according to claim 9, characterized in that the end cap (19) has a connector (17) which extends into an inner filter cavity (21) which is surrounded by a fluid-permeable support tube (37) and which is engaged by the tube socket (15) of the element receiver (13) in the filter housing (1) in the functional position of the filter element (11), and that, as the irregularity of shape which is pertinent on the end cap (19), the opening cross section of the connector (17) is matched to the non-circular outside contour (51) of the tube socket (15) of the element receiver (13), which contour forms the irregularity of shape of the element receiver (13). 